1. Technical Field
The present invention relates to a transflective liquid crystal display device capable of performing display in a transmitting mode and a reflecting mode, and an electronic apparatus using the same.
2. Related Art
An active driven twisted nematic (TN) liquid crystal display device has several advantages of thin size, light-weight, and low power consumption, so that it is widely employed as a display device of a portable telephone, a notebook computer, a portable television, a portable digital assistant (PDA), etc.
However, in the conventional twisted nematic liquid crystal display device, there exists a problem in a viewing angle that causes a display color to be changed or a display contrast to be degraded when the liquid crystal display device is viewed in a tilted angle due to a refractive index anisotropy of the liquid crystal molecule. That is, when a voltage is applied to a liquid crystal layer, the liquid crystal molecule is almost vertically aligned to show a positive one axial property, but a twisted angle has an S-shaped distribution, and the liquid crystal molecule is not significantly tilted near each surface of upper and lower substrates due to an effect of the alignment regulating force of the substrate surface. As a result, the configuration of the liquid crystal molecule when a voltage is applied thereto is differently shown depending on the angle of viewing the liquid crystal display device and its azimuth.
This is why improvement of the viewing angle problem is strongly desired in the liquid crystal display device, and various attempts are made for the improvement. As a representative method thereof, a method is disclosed which does not change the structure of the liquid crystal display device at all, but has an optical compensation film as a retardation plate incorporated into the conventional twisted nematic liquid crystal display device so as to increase the viewing angle.
A method of fabricating an optical compensation film used as the above-mentioned optical compensation film has been proposed, wherein the film is formed of a liquid crystalline polymer representing a positive one axial property optically and has fixed a nematic hybrid alignment which was formed in a liquid crystal state. This method has an advantage of cost effective production because it does not require fabrication equipment for the liquid crystal display device to be improved or additionally.
However, among various liquid crystal display devices, in a transflective liquid crystal display device in which a partially reflecting layer is interposed between a nematic liquid crystal layer and a lower polarizer, there occurs a problem that the amount of display light or contrast is not sufficient in a transmitting mode even though an optical compensation film functioning as the retardation plate is disposed. Thus, there exists a case that a plurality of retardation plates more than four is employed, however, which causes the cost to be increased and the display performance to be degraded due to a variation of the phase retardation axis of each retardation plate.
Accordingly, the present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a liquid crystal display device capable of improving the contrast or the amount of display light in a transmitting mode by using an optimized optical compensation film, and an electronic apparatus using the same.